In the field of helicopter construction, the main rotor is usually coupled via a rotor mast, coupled with the main rotor, with a helicopter rotor transmission, usually driven in the form of a planetary transmission. The rotor mast of a helicopter can be considered, by virtue of its function, to be a drive shaft for the main rotor.
In the case of the helicopter type “Eurocopter AS 350”, the rotor motor is, for example, coupled with a helicopter transmission comprising a planetary gear, in that the rotor mast can be fixed in a rotationally fixed manner in a central accommodation region of the helicopter transmission. Such a helicopter transmission is in turn housed in a transmission housing. The transmission housing is attached to the load-bearing structure of the helicopter at a plurality of points and is coupled to a rotor.
In the case of the “Eurocopter AS 350”, the planetary transmission has a plurality of externally-toothed planetary gears, which are mounted on associated planetary carriers. As dictated by the design the planetary gears are mounted in a locationally fixed gear ring, in the form of an internally-toothed ring gear, such that they can rotate about themselves and within the ring gear. In this case, the planetary gears respectively rotate about their planetary axis and simultaneously rotate or rotate about a central rotor mast axis within the gear ring. The rotation of the planetary gears is effected by a rotational drive of a central sun wheel, which is also locationally fixed, but is mounted such that it can rotate about the central rotor mast axis.
A drive rotates the central sun wheel so that the rotational movement is transferred, via the sun wheel and the planetary gears, via a planetary carrier, connected in a rotationally fixed manner to the planetary gears and acting as a force transfer device, onto the rotor mast, which in turn is connected with the planetary carrier in a rotationally fixed manner, wherein the rotor mast protrudes from the side of the transmission housing remote from the drive train side.
This corresponds to a compact, light, sufficiently powerful and robust arrangement of a rotor mast driven by a helicopter rotor transmission.
A fundamental problem of such rotor masts of known art, configured in such a manner and arranged in a helicopter is the guarantee of a smooth running operation.